(1) Field of the Invention
The instant invention relates to fiber optic rotary joints, and more particularly to a single in-line fiber optic rotary joint.
(2) Description of the Prior Art
Fiber optic rotary joints have heretofore been known in the art. In particular, fiber optic rotary joints have been used in oil exploration systems, seismic systems and sonar array systems as a means for passing optical and electrical power and data transmissions through two concentric or rotating bodies. As a specific example, when optical rotary joints are used in conjunction with ship-board sonar array systems, the optical rotary joints are integrated as part of the winch assembly, wherein during pay-out and retrieval of the sonar array systems, the optical rotary joints provide electrical and optical signal paths between the sonar array systems and the shipboard equipment.
Fiber optic couplings of the general type contemplated herein are described in the U.S. Patents to Hartkopf et al U.S. Pat. No. 4,680,809; Mruk U.S. Pat. No. 4,776,659; Chadha U.S. Pat. No. 5,007,697; and Snow et al No. 5,039,193 which represent the closest prior art to the subject invention of which the applicant is aware. More specifically, the patent to Hartkopf discloses a device for amplifying and coupling light paths between two optical channels LWL1 and LWL2. For channel LWL1, optical signals are converted to electrical signals and converted back to optical signals. The patent to Mruk discloses a flexible optical coupler including a light emitter unit for converting an input electrical signal to a corresponding light signal and a light detector unit for converting the light signal to a corresponding electrical output signal. The patent to Chadha concerns a fiber optic data coupler including an inlet fiber, an optical/electrical converter, an electrical/optical converter and an outlet fiber. The patent to Snow discloses a passive rotary joint for a single mode fiber optic path. The Snow joint is a mechanical joint closely aligning the ends of two optical fibers and it does not include any optical/electrical conversion devices.